Phosphorus acid esters of 5-phenyl-1,2,4-oxadiazolyl compounds

ABSTRACT

Oxadiazolyl compounds of the formula   wherein R1 represents C1-C4-alkyl, C1-C4-alkoxy or unsubstituted or substituted phenyl, R2 represents C1-C4-alkyl, R3 represents substituted phenyl, and X denotes oxygen or sulphur, a process for their production and their use for pest control.

United States Patent 1191 Meyer et al.

[451 Nov. 18, 1975 PHOSPHORUS ACID ESTERS OF S-PHENYL-l,2,4-OXADIAZOLYL COMPOUNDS [75] Inventors: Willy Meyer, Basel; Beat Bohner,

Binningen, all of Switzerland [73] Assignee: Ciba-Geigy Corporation, Ardsley,

22 Fi1ed: Mar. 12, 1973 21 App]. No.: 340,431

[30] Foreign Application Priority Data Fest 260/251 3,709,902 l/l973 Boyce et al. 260/307 G Primary Examiner-Raymond V. Rush Attorney, Agent, or Firm'l-larry Falber; Frederick H. Rabin [57] ABSTRACT Oxadiazolyl compounds of the formula wherein R represents C -Q-alkyl, C -C alkoxy or unsubstituted or substituted phenyl, R represents C -C -a1kyl, R represents substituted phenyl, and X denotes oxygen or sulphur, a process for their production and their use for pest control.

7 Claims, No Drawings PHOSPI-IORUS ACID ESTERS OF S-PHENYL-l,2,4-OXADIAZOLYL COMPOUNDS The present invention relates to oxadiazolyl compounds, to their production, and to their use for pest control. The oxadiazolyl compounds correspond to the formula wherein R represents C -C -alkyl, C -C -alkoxy or unsubstituted or substituted phenyl, R represents C -C alkyl, R represents substituted phenyl, and X denotes oxygen or sulphur. The alkyl and alkoxy groups denoted by R, and R can be straight chain or branched. Examples of such radicals are inter alia: methyl, methoxy, ethyl, ethoxy, propyl, propoxy, isopropyl, ixopropoxy, n-butyl, n-butoxy, i-, sec.-, tert.-butyl. The substituents on the phenyl radical in the case of R and R can be of the first or second order.

By substituents of the first order are meant basicityintensifying electron donors. These include the following groups: halogen atoms such as fluorine, chlorine, bromine or iodine; alkyl, monoand dihalogenoalkyl, alkoxy and alkylthio groups having 1 to 4 carbon atoms, which can be branched or unbranched, and are preferably unbranched and contain 1 to 2 carbon atoms; lower alkoxyalkyl groups, whereby the above definitions apply here too; prim, sec. and tert. amino groups, with lower alkyl and alkanoyl groups being preferred substituents; and hydroxyl and mercapto groups.

By substituents of the second order are meant acidifying electron acceptors. These include the following groups: nitro and cyano groups; trihalogenoalkyl groups, wherein halogen preferably denotes fluorine or chlorine; lower alkylsulphonyl or alkylsulphinyl groups containing a branched or unbranched alkyl radical having 1 to 4 carbon atoms, preferably an unbranched alkyl radical having 1 or 2 carbon atoms; sulphamyl and sulphamido groups, whereby the amino groups can carry one or two substituents, preferably lower alkyl groups, as defined above.

Preferred substituents on the phenyl ring are: halogen, preferably fluorine, chlorine and/or bromine, C C -alkyl, C -C -halogenoalkyl, particularly CF C C -alkoxy, C -C -alkylsulphinyl, C -C -alkylsulphonyl and/or nitro groups.

Compounds which are preferred on account of their action are those of formula I wherein R represents methyl, methoxy, ethyl, ethoxy, propyl or propoxy, R represents methyl, ethyl or propyl, R represents phenyl monoor polysubstituted by fluorine, chlorine, bromine, methyl, trifluoromethyl, methoxy, methylthio, ethoxy and/or nitro, and X represents sulphur.

The compounds of formula I are obtained by known methods; for example,

a. by reaction of a hydroxyoxadiazole of the formula c-on H RI HalP

(lll) in the presence of an acid-binding agent; or

b. by reaction of a salt of a hydroxyoxadiazole of formula II with a phosphoric acid halide of formula III. In formulae II and III, the symbols R R R and X have the meanings given for formula I, and Hal stands for fluorine, chlorine, bromine or iodine, but particularly for chlorine or bromine.

Salts of hydroxyoxadiazoles of formula II suitable for the process according to the invention are, for example, salts of monovalent metals, especially-the alkali metal salts. Acid-binding agents which can be used are: tertiary amines, e.g. trialkylamines, pyridine, or dialkylanilines; inorganic bases such as hydrides or hydroxides; carbonates and bicarbonates of alkali metals and alkaline-earth metals. It is sometimes necessary to use catalysts in the reactions, such as, e. g. copper or copper chloride.

The processes (a) and (b) are performed at 'a reaction temperature of between 0C and C, at normal pressure, and optionally in solvents or diluents. Suitable solvents or ,diluents are, for example, ethers and ethereal compounds, such as'diethyl ether, dipropyl ether, dioxane, dirnethoxyethane or tetrahydrofuran; amides such as N,N-dialkylated carboxylic acid amides; aliphatic, aromatic as well as halogenated hydrocarbons, particularly benzene, toluene, xylenes, chloro-v form or chlorobenzene; nitriles such as acetonitriles; DMSO, and ketones such as acetone or methyl ethyl ketone.

The starting materials of formulae II and III are in some cases known, or can be produced by methods analogous to known methods.

The compounds of formula I have a broad biocidal action, and can be used therefore for the control of a wide variety of plant and animal pests.

The said compounds are particularly suitable for the vcontrol of insects of the families: Acrididae, Blattidae,

Gryllidae, Gryllotalpidae, Tettigoniidae, Cimicidae,

Phyrrhocoridae, Reduviidae, Aphididae, Delphacidae, v

Diapsididae, Pseudococcidae, Chrysomelidae, Coccinellidae, Bruchidae, Scarabaeidae, Dermestidae, Tenebrionidae, Curculionidae, T ineidae, Noctuidae, Lymantriidae, Pyralidae, Galleridae, Culicidae, Tipulidae, Stomoxydae, Muscidae, Calliphoridae, Trypetidae and Pulicidae; as well as acarids of the families: Ixodi- Organic phosphorus compounds Bis-0,0-diethylphosphoric acid anhydride (TEPP) Dimethyl-( 2,2,2-trichlorol -hydroxyethyl )-phosphonate (TRlCl-ILORFON) 9 -5 ,6 ,7 ,8-tetrahydronap hthyl-N-methyl-carbamate 3-isopropyl-4-methylthio phenyl-N-methylcarba-,

mate I 3,5-dimethyl-4-methoxy-phenyl-N-methylcarbamate 3-methoxymethoxy-phenyl-N-methylcarbamate 3-allyloxyphenyl-N-methylcarbamate 2-propargyloxymethoxy-phenyl-N-methyl-carbamate 2-allyloxyphenyl-N-methyl-carbamate 4-methoxycarbonylamino-3-isopropylphenyl-N- methyl-carbamate 3,5-dimethyl-4-methoxycarbonylamino-phenyl-N- methyl-carbamate Z-y-methylthiopropylphenyl-N-methyl-carbamate 3-( a-methoxymethyl-2-p ropenyl )-phenyl-N-methylcarbamate I 2-chloro-5-tert.-butyl-phenyl-N-methyl-carbamate 4-(methyl-propargylamino-3,S-XyIyI-N-methyI-car bamate v 4-(methyl-y-chloroallylamino)-3,5-xylyl-N-methylcarbamate 4-(methyl-B-chloroallylamino)-3,5-xylyl-N-methylcarbamate l-( ,B-ethoxycarbonylethyl )-3-methyl-5 -pyrazolyl- N,N-dimethylcarbamate 3-methyl-4-(dimethylamino-methylmercaptomethyleneimino)phenyl-N-methylcarbamate l ,3-bis(carbamoylthio )-2-( N,N-dimethylamino)- propanehydrochloride 5,5-dimethylhydroresorcinoldimethylcarbamate 2- ethyl-p ropargylamino ]-phenyl-N-methylcarbamate 2-[methyl-propargylamino]-phenyl-N-methylcarbamate 2-[dipropargylamino]-phenyl-N-methylcarbamate 4-[dipropargylamino1-3-tolyl-N-methylcarbamate 4-[dipropargylamino1-3,5-xylyl-N-methylcarbamate 2-[allyl-isopropylamino]-phenyl-N-methylcarbamate 3-[allyl-isopropylamino]-phenyl-N-methylcarbarnate Chlorinated Hydrocarbons 'yhexachlorocyclohexane [GAMMEXANE LIN- DAN; 'y I-lCI-I] v I l,2,4,5 ,6,7 ,8,8-octachIoro-3a,4,7,7a'tetrahydro-4,7-

methylene indane [CHLORDAN] l ,4,5 ,6,7,8 ,8-heptachloro,3a,4,7,7a-tetrahydro-4,7-

methylene indane [HEPTACI-ILOR] v l ,2,3,4,10,lO-hexachloro-l,4,4a,5,8,8a-hexahydroendol ,4 -exo-5 ,S-dimethanonaphthalene [AL- DRIN] 1,2,3 ,4, l 0, lO-hexachloro- 6,7-epoxyl ,4,4a,5,6,7,8- ,8a-octahydro-exo-1 ,4-endo-5 ,8-dimethanonaphthalene [DIELDRIN] 1 ,2,3,4, lO-hexachloro-5,7-epoxyl ,4,4a,5,6,7,8-

,8a-octahydro-endo-endo-5,8-dimethanonaphthalene [ENDRIN].

In addition to possessing the above mentioned properties, the compounds of formula I are also effective against members of the division Thallophyta. Some of these compounds thus have a bactericidal action. They are particularly effective, however, against fungi, especially against phytopathogenic fungi belonging to the following classes: Oomycetes, Zygomycetes', Ascomycetes, Basidiomycetes and Denteromycetes. The compounds of formula I have moreover a fungitoxic action in the case of fungi which attack plants from the soil. Furthermore, the new active substances are suitable for the treatment of seeds, fruits,tubers, and so forth, to obtain protection against fungus infections. The com- I pounds of formula I are suitable also for the control of phytopathogenic nematodes.

The compounds of formula I can be used on their own or together with suitable carriers and/0r additives. Suitable carriers and additives may be solid or liquid, and correspond to the substances common in formulation practice, such as, e.g. natural and regenerated substances, solvents, dispersing agents, wetting agents, ad-

hesives, thickeners, binders and/or fertilisers.

For application, the compounds of formula I can be processed into the form of dusts, emulsion concentrates, granulates, dispersions, sprays, or solutions, the formulation of these preparations being effected in a manner commonly known in practice. Also to be mentioned are cattle dips and spray races, in which aqueous preparations are used.

'The agents according to the inventionare produced in a manner known per se by the intimate mixing and- /or grinding of active substances of formula I with the suitable carriers, optionally with the addition of dispersing agents or solvents which are inert to the active substances. The active substances can be obtained and used in the following preparation forms: solid preparations:

dusts, scattering agents, granulates, coated granulates, impregnated granulates and homogeneous granulates; liquid preparations:

a. water dispersible active substance concentrates: wettable powders, pastes, emulsions;

b. solutions.

The solid preparations (dusts, scattering agents) are produced by the mixing of the active substances with solid carriers. Suitable carriers are, e.g. kaolin, talcum, bole, loess, chalk, limestone, ground limestone, attapulgite, dolomite, diatomaceous earth, precipitated silicic acid, alkaline-earth silicates, sodium and potassium aluminium silicates (feldspar and mica), calcium and magnesium sulphates, magnesium oxide, ground synthetic materials, fertilisers such as ammonium sulphate, ammonium phosphate, ammonium nitrate, urea, ground vegetable products such as bran, bark dust, sawdust, ground nutshells, cellulose powder, residues of plant extractions, active charcoal, etc., alone or in admixture with each other.

Granulates can be very easily prepared by a process in which an active substance of formula I is dissolved in an organic solvent, the thus obtained solution applied to a granulated mineral, e.g. attapulgite, SiO granicalcium, bentonite, etc., and the organic solvent then evaporated off.

It is possible also to produce polymer granulates; in this case the active substances of formula I are mixed with polymerisable compounds (urea/formaldehyde; dicyandiamide/formaldehyde; melamine/formaldehyde, or others); polymerisation is then carefully carried out in a manner which leaves the active substances unaffected, and granulation performed actually during the gel forming process. It is more favourable, however,

to impregnate finished porous polymer granules (urea/- formaldehyde, polyacr'ylonitrile, polyester and others), having a specific surface area and a favourable predeterminable adsorption/desorption ratio, with the active substances, e.g. in the form of their solutions (in a lowboiling solvent), and to then remove the solvent. Polymer granulates of this kind can be also sprayed in the form of 'microgranulates, having bulk weights of preferably 300 g/liter to 600 g/liter, with the aid of spray ap- 1 1 paratus. Spraying can be carried out over extensive areas of useful plant crops by the use of aeoplanes.

Granulates can also be obtained by the compacting of the carrier material with the active substances and additives, and a subsequent reducing operation.

Moreover, it is possible to add to these mixtures additives stabilising the active substance and/or nonionic, anion-active and cation-active substances which improve, e.g. the adhesiveness of the active substances on plants and parts of plants (adhesives and agglutinants), and/or ensure a better wettability (wetting agents) as well as dispersibility (dispersing agents).

The following substances are, for example, suitable:

olein/lime mixture, cellulose derivatives (methyl cellulose, carboxymethyl cellulose), hydroxyethylene glycol ethers of monoalkyl and dialkyl phenols having 5 to ethylene oxide radicals per molecule and 8 to 9 carbon atoms in the alkyl radical, lignin-sulphonic acid, the alkali metal and alkaline-earth metal salts thereof, polyethylene glycol ethers (carbowaxes), fatty alcohol polyglycol ethers having 5 to ethylene oxide radicals per molecule and 8 to 18 carbon atoms in the fatty alcohol moiety, condensation products of ethylene oxide, propylene oxide, polyvinylpyrrolidones, polyvinyl alcohols, condensation products of urea and formaldehyde, as well as latex products.

Water-dispersible concentrates of active substances, i.e. wettable powders, pastes and emulsion concentrates, are agents which can be diluted with. water to obtain any desired concentration. They consist of active substance, carrier, optionally additives which stabilise the active substance, surface-active substances, and anti-foam agents and, optionally, solvents.

The wettable powders and pastes are obtained by the mixing and grinding of the active substances with ,dispersing agents and pulverulent carriers, in suitable devices, until homogeneity is obtained. Suitable carriers are, e.g. those previously mentioned in the case of solid preparations. It is advantageous in some cases to use mixtures of different carriers. As dispersing agents it is possible to use, e.g.: condensation products of sulphonated naphthalene and sulphonated naphthalene derivatives with formaldehyde, condensation products of naphthalene or of naphthalene-sulphonic acids with phenol and formaldehyde, as well as alkali, ammonium and alkaline-earth metal salts of ligninsulphonic acid, also alkylarylsulphonates, alkali metal salts and alkaline-earth metal salts of dibutyl naphthalenesulphonic acid, fatty alcohol sulphates such as salts of sulphated hexadecanols, heptadecanols, octadecanols, and salts of sulphated fatty alcohol glycol ethers,;the sodium salt of oleyl methyl tauride, ditertiary ethylene glycols, dialkyl dilauryl ammonium chloride, and fatty acid alkalimetal and alkaline-earth metal salts.

Suitable anti'foam agents are, e.g. silicones.

The active substances are so mixed, ground, sieved and strained with the above mentioned additives that the solid constituent in the case of wettable powders has a particle size not exceeding 0.02 to 0.04 mm, and in the caseof pastes not exceeding 0.03 mm. For the preparation of emulsion concentrates and pastes, dispersing agents are used such as those mentioned in the preceding paragraphs, organic solvents and water. Suitable solvents are, e.g. alcohols, benzene, xylene, toluene, dimethylsulphoxide, and mineral oil fractions boiling in the range of 120 to 350C. The solvents must be practically odourless, nonphytotoxic, and inert to the active substances.

Furthermore, the agents according to the invention can be used in the form of solutions. For this purpose, the active substance, or several active substances, of the generalformula l is dissolved in suitable organic solvents, solvent mixtures, or water. As organic solvents it is possible to; use aliphatic and aromatic hydrocarbons, their chlorinated derivatives, alkylnaphthalenes, mineral oils on their own or in admixture with each other.

The content of active substance in the above described agents is between 0.1 and it is to be mentioned in this connection that in the case of application of the agents from an aeroplane, or by means of some other suitable application devices, concentrations of up to 99.5% can be used, or even the pure active substance.

The active substances of formula 1 can be prepared, e.g. as follows:

Dusts The following substances are used for the preparation of (a) a 5% dust, and (b) a 2% dust:

a. 5 parts of active substance 95 parts, of talcum.

b. 2 parts of active substance 1 part of highly dispersed silicic acid 97 parts of talcum.

The active substances are mixed and ground with the carriers.

Granulate wettable powder The following constituents are used for the preparation of (a) a 40%, (b) and (c) a 25%, and (d) a 10% wettable powder:

a. 40 parts of active substance,

5 parts of sodium lignin sulphonate,

l part of sodium dibutyl-naphthalene sulphonate,

54 parts of silicic acid.

b. 25 parts of active'substance,

4.5 parts of calcium lignin sulphonate 1.9 parts of Champagne chalk/hydroxyethyl cellulose mixture (1:1),

1 .5 parts of sodium dibutyl naphthalene sulphonate,

19.5 parts of silicic acid,

19.5 parts of Champagne chalk,

28.1 parts of kaolin.

c. 25 parts of active .substance,

2.5 parts of isooctylphenoxy-polyoxyethyleneethanol, 1.7 parts of Champagne chalk/hydroxyethyl cellulose mixture (1:1), I

8.3 parts of sodium aluminium silicate,

16.5 parts of kieselguhr,

46 parts of kaolin.

13 cl. 10 parts of active substance, 3 parts of a mixture of the sodium salts of saturated fatty alcohol sulphates, 5 parts of naphthalenesulphonic acid/formaldehyde condensate, 5 82 parts of kaolin. The active substances are intimately mixed, in suitable mixers, with the additives, the mixture being then ground in the appropriate mills and rollers. Wettable powders are obtained which can be diluted with water to give suspensions of any desired concentration.

Emulsifiable concentrates The following substances are used to produce (a) a 10% and (b) a 25% emulsifiable concentrate:

a. 10 parts of active substance,

3.4 parts of epoxidised vegetable oil,

13.4 parts of a combination emulsifier consisting of fatty alcohol polyglycol ether and alkyla'rylsulphonate calcium salt,

40 parts of dimethylformamide,

43.2 parts of xylene.

b. parts of active substance,

2.5 parts of epoxidised vegetable oil,

10 parts of an alkylarylsulphonate/fatty alcoholpoly- 25 glycol ether mixture 5 parts of dimethylformamide,

57.5 parts of xylene.

From these concentrates it is possible to produce, by dilution with water, emulsions of any desired concen- 3O tration.

Spray:

The following constituents are used to prepare a 5% spray:

5 parts of active substance,

1 part of epichlorhydrin,

94 parts of ligroin (boiling limits 160l90C).

EXAMPLE 1 40 Production of O ,O-diethyl-O-[S -(4-methylphenyl)-l ,2 ,4-oxadiazo1yl- (3 ]-thiophosphate Preparation of the starting material a. l 1.0 g of hydroxylamine.HCl and 20.8 g of K CO are refluxed in 300 ml of abs. tetrahydrofuran for 2 hours. An addition is then made dropwise at 30- 35C within 15 minutes of 25 g of 4-methylbenzoylisocyanate in 125 ml of tetrahydrofuran. After 2 hours boiling the solvent is removed. The yellow product is dissolved in 500 ml of H 0 and 75 ml of conc. NaOH. After the solution has been filtered until clear, the product is precipitated with conc. HCl. After processing and recrystallisation, the isolated 3-hydroxy-5-(4- methylphenyl)-1,2,4-oxadiazole has a melting point of 203- 207C. Analysis: calculated: C, 61.35; H 4.58; N 18.16, found: C, 61.2; H 4.50; N 18.60.

Preparation of the final product crystallisation from CH OH, there is obtained 0,0- diethyl-O-[5-(4-methylphenyl)]-1 ,2,4-oxadiazolethiophosphate, M.P. 22- 23C. Analysis: calculated: C, 47.56%; H 5.22%; P 9.43%; found: C, 47.20%; H 5.30%; P 9.40%.

The following compounds too are produced in an analogous manner:

a 17 EXAMPLE 2 A. Insecticidal stomach poison action Cotton and potato plants were sprayed with a 0.05%

aqueous active-substance emulsion (-obtained from a emulsifiable concentrate).

After the drying of the obtained coating, Spodoptera litoralis or Heliothis virescens larvae L were placed onto the cotton plants, and Colorada beetle larvae (Leptinotarsa decemlineata) onto the potato plants. The test was carried out at 24C with 60% relative humidity.

The compounds according to Example 1 exhibited in the above test a good insecticidal stomach. poison action against Spodoptera litoralis, Heliothis and Leptinotarsa decemlineata larvae.

B. Systemic insecticidal action In order to determine the systemic action, rooted bean plants (Vicia faba) were placed into a 0.01% aqueous active-substance solution (obtained from a 10% emulsifiable concentrate). After a period of 24 hours, bean aphids (Aphis fabae) were placed onto the parts of the plants above the soil. The insects were protected by a special device from the effects of contact and of gas. The test was carried out at 24C with 70% relative humidity.

In the above tests, the compounds according to Example 1 exhibited a systemic action against Aphis fabae.

EXAMPLE 3 Action against Chilo suppressalis Rice plants of the type Caloro were planted, 6 plants per pot, in plastic pots having a top diameter of 17 cm, and grown to a height of ca. 60 cm. Infestation with Chilo suppressalis larvae (L 3-4 mm long) was carried out 2 days after application of the active substance in granular form (amount applied 8 kg of active substance per hectare) to the paddy water. The evaluation of the insecticidal action was made 10 days after application of the granules.

The compounds according to Example 1 were effective against Chilo suppressalis in the above test.

EXAMPLE 4 Action against ticks A. Rhipicephalus bursa In each case, 5 adult ticks or 50 tick larvae were placed into a small glass test tube, and the test tubes then immersed for l to 2 minutes in 2 ml of an aqueous emulsion from a dilution series of 100, l0, 1 and 0.1 ppm of test substance. The tubes were then sealed with a standardised cotton plug, and inverted so that the ac tive substance emulsion could be absorbed by the cotton wool.

An evaluation in the case of the adults was made after 2 weeks, and in the case of the larvae after 2 days. There were two repeats for each test.

B. Boophilus microplus (larvae) tests were carried out with sensitive larvae and OP- 18 resistant larvae, respectively (resistance is with respect to diazinon compatibility).

The compounds according to Example 1 were effective in these tests against adults and larvae of Rhipicephalus bursa and against sensitive and OP-resistant larvae, respectively, of Boophilus microplus.

EXAMPLE 5 Acaricidal action Phaseolus vulgaris (plants) were infested, 12 hours before the test for acaricidal action, with an infested piece of leaf from a mass culture of Tetranychus urticae. The transferred mobile stages were sprayed with the emulsified test preparations from a chromatography-sprayer in a manner ensuring no running off of the spray liquor. An assessment was made after 2 to 7 days, by examination under a binocular, of the living and of the dead larvae, adults and eggs, and the results expressed in percentages. The treated plants were kept during the holding time in greenhouse compartments at 25C.

The compounds according to Example 1 were effective in the above test against adults, larvae and eggs of Tetranychus urticae.

EXAMPLE 6 Action against soil nematodes In order to test the action against soil nematodes the active substances were added, in the concentration stated in each case, to soil infested with root-gallnematodes (Meloidogyne arenaria), and the whole intimately mixed. In the one test series, tomato seedlings were planted immediately afterwards in the thus prepared soil, and in the other test series tomatoes were planted after a waiting time of 8 days. 1

For an assessment of the nematocidal action, the galls present on the roots were counted 28 days after planting and sowing, respectively.

The active substances according to Example 1 exhibited in this test a good action against Meloidogyne arenaria.

We claim:

1. A compound of the formula wherein R represents ethyl, methoxy or ethoxy, R represents methyl or ethyl, R represents phenyl monosubstituted by methyl, methoxy, cyano, fluorine, chlorine, bromine or nitro, or phenyl di-substituted by chlorine, and X represents sulfur.

2. A compound according to claim 1, wherein R represents phenyl monosubstituted by methyl or chlorine.

3. Compound according to claim 1 of the formula 5 O-N oc H, C 1.1 2

4. Compound according to claim 1 of the formula OCH-3 5. Compound according to claim 1 of the formula 6. Compound according to claim 1 of the formula UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 920,676 Dated NwemBe'r 18, 1975 Will Meyer et a1.

Inventor (s) It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

The term of this patent subsequent to September 2 1992 has been disclaimed.

Signed and Scaled this seventeenth D 3} of February 1 976 [SEAL] A ttes t:

RUTH C. MASON C. MARSHALL DANN Arresting Officer Commissioner of Parents and Trademarks 

1. A COMPOUND OF THE FORMULA
 2. A compound according to claim 1, wherein R3 represents phenyl monosubstituted by methyl or chlorine.
 3. Compound according to claim 1 of the formula
 4. Compound according to claim 1 of the formula
 5. Compound according to claim 1 of the formula
 6. Compound according to claim 1 of the formula
 7. Compound according to claim 1 of the formula 